A great number of such and comparable thrust-generating devices have been known from the patent literature.
An engine arrangement with at least one longitudinal thrust engine, i.e., a main engine, and a plurality of lateral thrust engines, in which all engines are designed as liquid-fuel engines and separate tanks are provided for the fuel and the oxidizing agent, has been known from DE-PS 20 57 326. All engines are supplied with fuel by a common turbopump system. The engines can be operated individually and together by means of corresponding valves. The fuel supply selected makes the lateral thrust engines dependent on the main engine in terms of design and operation, so that the lateral thrust-generating device cannot be handled, e.g., replaced, retrofitted or used for other purposes, as a separate unit.
The advantages of liquid-fuel engine systems, such as high specific impulse, long to extremely short combustion times, multiple ignitions, etc., are contrasted by major drawbacks in terms of safety engineering. Liquid rocket fuels may be chemically aggressive, especially corrosive, environmentally hazardous or even highly toxic, and, depending on the temperature, they may develop high inherent pressures during storage. At any rate, they are inflammable and explosive, and hypergolic fuel combinations and single-component fuels that can be catalytically activated are especially critical.
These disadvantages have to date prevented any relevant use of liquid-fuel engine systems especially for military purposes, where storage over several years, rough handling and, in the case of defense, shelling, the effect of fire, etc., can be expected. It should also be mentioned that if the tanks leak due to the development of leaks, shelling, etc., liquid rocket fuels are discharged and may very rapidly occupy a large surface, spreading over great distances (generation of gas), which may have devastating consequences, especially in ships, in conjunction with the fire and explosion hazards.
Therefore, despite their disadvantages, such as single ignition, limited controllability of the throughput, fuel depositions in flow channels, valves, etc., no extremely short combustion time, etc., solid rocket fuels are used almost exclusively for the propelling and the lateral thrust control of military missiles, rockets and shells.
Examples of such lateral thrust control devices with solid fuel propellant charges are described in, e.g., DE-OS 35 31 686 and DE-OS 35 21 204.